Calprotectin

INTRODUCTION
Intended Use
The DRG:HYBRiD-XL Calprotectin is an enzyme immunoassay for the quantitative in vitro diagnostic measurement of Calprotectin in stool.Only for use with the DRG:HYBRiD-XL Analyzer.Summary and ExplanationCalprotectin is a calcium-binding protein secreted predominantly by neutrophils and monocytes. Fecal calprotectin is a marker for acute inflammation in general and for neoplastic and inflammatory gastrointestinal diseases (1-3). It is often difficult to distinguish between irritable bowel syndrome and chronic inflamma¬tory bowel disease. This can lead to extensive and unnecessary colonoscopic examinations. In contrast, the fecal calprotectin test allows clear differentiation between patients with inflammatory bowel disease (acute Morbus Crohn‘s disease and ulcerative colitis) and irritable bowel syndrome (4-9). Fecal calprotectin levels correlate significantly with histologic and endoscopic assessment of disease activity in Morbus Crohn‘s disease and ulcerative colitis as well as with the fecal excretion of indium-111-labelled neutrophilic granulocytes that has been suggested as the “gold standard“ of disease activity in inflammatory bowel disease (10). Elevated levels of calprotectin are a much better predictor of relapse of inflammatory bowel disease than standard inflamma-tory markers (11). Comparing this marker with standard fecal occult blood screening in colorectal cancer demonstrates clearly the diagnostic advantages of the fecal calprotectin test. The parameter is of a high diagnostic value: if the calprotectin level in stool is low, the probability is high that no organic intestinal disease exists.PRINCIPLE OF THE TESTThe DRG:HYBRiD-XL Calprotectin Kit is a solid phase enzyme-linked immunosorbent assay (ELISA) based on the sandwich principle. The antibody coated wells (ACW) of the reagent cartridges are coated with a monoclonal (mouse) antibody directed towards a unique antigenic site of the Calprotectin molecule. An aliquot of patient sample containing endogenous Calprotectin is incubated in the coated well with enzyme conjugate, which is a monoclonal anti-Calprotectin antibody conjugated with horseradish peroxidase. After incubation the unbound conjugate is washed off. The amount of bound peroxidase conjugate is proportional to the concentration of Calprotectin in the sample. Having added the substrate solution, the intensity of color developed is proportional to the concentration of Calprotectin in the patient sample.